Contextual influence on movement was examined for a selection of everyday activities. Non-medicated and medicated Parkinson's disease (PD) patients and control subjects reached for a drinking glass target from both seated and standing postures, and stepped over a surface-level obstacle while walking on a constrained path. Contextual challenge was increased in the seated reach by filling the glass with water, in the standing reach by increasing the depth of the gap between the target and stationary foot position, and in the obstacle negotiation trials by raising the gait path surface above the floor level. In all cases, behaviour among PD patients was uniquely disrupted by contextual challenge. In addition, benefits of conventional medication therapy for PD patients were limited in challenging contexts. The results suggest an adapted movement control mechanism at work in PD patients, with the neural resources used in this adapted response prone for interference during contextual challenges.

en

dc.language.iso

en_US

en

dc.publisher

Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2006